Methods and apparatuses for wiping subterranean casings

ABSTRACT

An object for wiping a subterranean casing is described herein. The object may include an inner core with a first width. The ball may also include a deformable layer surrounding the inner core. The deformable layer may have a second width. The first width may be smaller than a diameter of at least one baffle within the subterranean casing. The second width may be larger than or equal to the largest inner diameter of the subterranean casing.

BACKGROUND

The present disclosure relates generally to subterranean operations, and, more particularly, the present disclosure relates to methods and apparatuses for wiping subterranean casings.

Subterranean operations typically include casings within a borehole. Fluids may be forced down the casing as part of drilling, treatment, and production operations, intended to either prepare the formation to produce a desired fluid, or maximize the desired fluid produced from the formation. In certain instances, a fluid forced down the casing, including cement, may leave residue on an interior surface of the casing. The residue may need to be removed to prevent it from contaminating other fluids and damaging other equipment located downhole. In certain instances, wipers are placed within the casing string to wipe the interior surface of the casing. Unfortunately, wiping the interior surface of the casing can be problematic, given that the casing may include different interior diameters and obstructions, including baffles and bends, that may cause a wiper to get stuck.

FIGURES

Some specific exemplary embodiments of the disclosure may be understood by referring, in part, to the following description and the accompanying drawings.

FIG. 1 a illustrates a cross section of an example wiper object, according to aspects of the present disclosure.

FIG. 1 b illustrates a cross section of an example wiper object, according to aspects of the present disclosure.

FIGS. 2 a illustrates an example wiper object wiping a subterranean casing, according to aspects of the present disclosure.

FIGS. 2 b illustrates an example wiper object wiping a subterranean casing, according to aspects of the present disclosure.

FIGS. 2 c illustrates and example wiper object wiping a subterranean casing, according to aspects of the present disclosure.

While embodiments of this disclosure have been depicted and described and are defined by reference to exemplary embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.

DETAILED DESCRIPTION

The present disclosure relates generally to subterranean operations, and, more particularly, the present disclosure relates to methods and apparatuses for wiping subterranean casings.

Illustrative embodiments of the present disclosure are described in detail herein. In the interest of clarity, not all features of an actual implementation may be described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the specific implementation goals, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of the present disclosure.

To facilitate a better understanding of the present disclosure, the following examples of certain embodiments are given. In no way should the following examples be read to limit, or define, the scope of the disclosure. Embodiments of the present disclosure may be applicable to horizontal, vertical, deviated, or otherwise nonlinear wellbores in any type of subterranean formation. Embodiments may be applicable to injection wells as well as production wells, including hydrocarbon wells.

FIGS. 1 a and 1 b show a cross section of an example wiper object 100, or wiper ball 100, according to aspects of the present disclosure. As can be seen, the wiper object 100 includes a spherical or ball shape. Although the wiper object 100 may be shown with the spherical of ball shape, other shapes are possible, as would be appreciated by one of ordinary skill in view of this disclosure. The wiper object 100 may comprise an inner core 104 with a width 104 a. In the embodiment shown in FIG. 1, the inner core 104 is spherical and the width 104 a comprises a diameter of the inner core 104. The width 104 a may be smaller than a diameter of a casing obstruction, such as a baffle, as will be described below. Although the inner core 104 is described as spherical, a perfect sphere is not required—any generally rounded shape with a generally consistent diameter may be considered spherical within the scope of this disclosure. In certain embodiments, the inner core 104 may be comprised of solid materials, such as composites, thermal plastics, ceramics, particulates, and other similar materials. In certain other embodiments, the inner core 104 may be comprised of metal. The inner core 104 may be resistant to deforming when subjected to pre-determined pressures, as will be discussed below.

A deformable layer 102 with an uncompressed width 102 a may surround the inner core 104, concentric with the inner core 104. In the embodiment shown, the deformable layer 104 includes a spherical shape, and the width 102 a comprises a diameter of the deformable layer, but a spherical shape is not required. Other shapes are possible, as would be appreciated by one of ordinary skill in view of this disclosure. The uncompressed width 102 a may be larger than or equal to a largest inner diameter of a subterranean casing, as will be described below. In certain embodiments, the deformable layer may be composed of an elastomeric foam, including, but not limited to, open-cell foams consisting of natural rubber, nitrile rubber, styrene butadiene rubbers, and polyurethane. The deformable layer may also me composed of a gel material. Although certain example compositions are stated above with respect to deformable layer 102 and inner core 104, one of ordinary skill in the art in view of this disclosure will appreciate the appropriate material for both the deformable layer 102 and inner core 104 given the requirements of a particular application.

In certain embodiments, a wiper object, such as the wiper object 100 in FIGS. 1 a and 1 b may be used in a multi-zone treatment operation. In such an operation a subterranean string, such as a casing string, may include multiple sleeves, which slide open to expose the surrounding formation to treatment fluids and pressures. One example treatment operation is a multi-zone fracturing operation, whereby sleeves are used to selectively fracture portions of a formation. In such embodiments, the sleeves may includes steel baffles which project into the interior bore of a subterranean casing, and restrict the subterranean casing to a diameter less that the inner diameter of the subterranean casing.

An example subterranean string, casing string 206, with example sleeves 208 and 212, is shown in FIGS. 2 a-c. The casing string 206 is shown disposed within a borehole 252 in a subterranean formation 250. The sleeves 208 and 212 may include steel baffles 210 and 214, respectively, and may be positioned adjacent to locations of interest within the subterranean formation 250. Baffle 210 may have an inner diameter 210 a, and baffle 214 may have an inner diameter 214 a. The inner diameter of a baffle may refer to the diameter of the opening defined by the baffle. In certain embodiments, the inner diameters 210 a and 210 b may be 2.415 inches. As can be seen, the inner diameters 210 a and 214 a are smaller than a largest inner diameter 206 a of the casing string 206, which, in certain embodiments may be 5.5 inches. The casing string 206 may also include a landing profile 216 at a distal end. The landing profile 216 may have a diameter 216 a, less than the inner diameters 210 a and 214 a of the baffler 210 and 214, and less that the largest inner diameter 206 a of the casing string 206. In certain embodiments, as will be described below, an example wiper object 200 may be sized to wipe an inner surface of the casing string 206, pass through the baffles 210 and 214, and sealingly engage with a landing profile 216, closing off the casing string 206.

In FIGS. 2 a-c, an example wiper object 200 in the shape of a wiper ball is disposed within the inner bore of the casing string 206. The wiper object 200 may include an inner core 204 and a deformable layer 202, with first and second widths similar to those described above with respect to the example wiper object 100 in FIGS. 1 a and 1 b. The width of the deformable layer 202 may be larger than the largest inner diameter 206 a of the casing string 206, or at least equal to the diameter 206 a, such that the deformable layer 202 is compressed upon entering the casing string 206. For example, in the case where the largest inner diameter 206 a of the casing string 206 is 5.5 inches, the width of the deformable layer 202 may be 7 inches. Making the width of the deformable layer 202 larger than the largest inner diameter 206 a of the casing string 206 may increase the wiping effectiveness of the wiper object 200 by ensuring contact between the wiper object 200 and the inner surface of the casing string 206.

As will be shown in FIGS. 2 b and 2 c, the width of inner core 204 may be smaller than the diameters 210 a and 214 a of baffles 210 and 214, and larger than diameter 216 a of landing profile 216. For example, in the case where the diameters 210 a and 214 a of the baffles 210 and 214 are 2.415 inches, the width of the inner core 204 may be 1.5 inches. By making the width of the inner core 204 smaller than the diameters 210 a and 214 a of the baffles 210 and 214, the wiper object 200 may pass through the baffles, 210 and 214, wiping the entire length of the casing string 206. Additionally, by making the width of the inner core 204 larger than the diameter 216 a of the landing profile, the wiper object 200 may sealingly engage with the landing profile. In certain embodiments, the diameters 210 a and 214 a of the baffles 210 and 214 may differ. In those instances, the width of the inner core 204 may be smaller than both diameters 210 a and 214 a, or the width of the inner core 204 may be smaller than one diameter and larger than the other, such that the inner core 204 sealingly engages with one of the baffles, effectively treating a baffle as a landing profile.

Once a wiper object, such as wiper object 200, is disposed within a subterranean casing, such as casing string 206, the wiper object may be forced away from the surface by, for example, pumping a fluid behind the wiper object. In FIG. 2 a, the wiper object 200 is being forced downwards toward sleeve 208 and baffle 210, as indicated by the arrow. As the wiper object 200 is pumped downward, it may remain in contact with the inner surface of the casing string 206, wiping the inner surface of the casing string 206. As would be appreciated by one of ordinary skill in the art in view of this disclosure, the rounded shape of the wiper object 200 decreases the likelihood that the wiper object 200 will become lodged in the casing string 206 before passing to the landing profile 216.

FIG. 2 b shows the wiper object 200 passing through the baffle 210. As the wiper object 200 passes through the baffle 210, the deformable layer 202 deforms and compresses. The inner core 204 may pass through the baffle 210 because the width of the inner core 204 is less than the diameter 210 a of the baffle 210. Advantageously, the spherical shape of the inner core 204 may reduce the likelihood of the wiper object 200 becoming lodged at the baffle 210 because the inner core 204 does not include edges which may catch on the baffle 210. Additionally, the spherical shape of the inner core 204, and the sizing of the inner core relative to the baffle 210 may decrease the pressure required to force the wiper object 200 through the baffle 210.

Once the wiper object 200 has passed through the baffle 210, the deformable layer 202 may re-expand to contact the inner surface of the casing string 206. The deformable layer 202 of the wiper object 200 may remain in contact with the inner surface of the casing string 206 until it encounters sleeve 212 and baffle 214. The deformable layer 202 may then deform as the wiper object 200 and inner core 204 pass through the baffle 214 in a similar manner to that shown with respect to baffle 210.

After the wiper object 200 has passed through the baffle 214, the deformable layer 202 may again re-expand to contact the inner surface of the casing string 206 as the wiper object 200 is forced towards the landing profile 216 as a distal end of the casing string. Once the wiper object 200 clears the baffle 214, the fluid forcing the wiper object downward may cause wiper object 200 to sealingly engage with the landing profile 216. As can be seen in FIG. 2 c, the deformable layer 202 may deform as the wiper object 200 contacts the landing profile 216. Instead of passing through the landing profile 216, though, the inner core 204 of the wiper object may become lodged on the landing profile 200, because the width of the inner core is greater than the diameter 216 a of the landing profile. Notably, the compressed, deformable layer 202 and inner core 204 may prevent fluid from escaping through the landing profile 216, sealing inner bore of the casing string 206. The rounded shape of the wiper object 200 and inner core 204 may increase the likelihood that the wiper object 200 and inner core 204 will contact and sealingly engage with the landing profile.

In certain embodiments, once the wiper object 200 has landed on the landing profile the internal pressure within the casing string 206 may be increased to open sleeve 208 and 212. In such instances, the inner core 204 of the wiper object 200 may need to withstand the increased pressure without deforming, as the seal with the landing profile may be broken if the inner core 204 deforms. For example, in certain embodiments, the inner core 204 may need to withstand 2500 psi of pressure without deforming. The pressure rating for the inner core 204 may change depending on the application, however, and one of ordinary skill in the art in view of this disclosure will appreciate the composition of the inner core 204 required to withstand the pressure rating.

Therefore, the present disclosure is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the present disclosure. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. The indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces. 

What is claimed is:
 1. An object for wiping a subterranean casing, comprising: an inner core, wherein the inner core has a first width; and a deformable layer surrounding the inner core, wherein the deformable layer has a second width; wherein: the first width is smaller than a diameter of at least one baffle within the subterranean casing, and the second width is larger than or equal to a largest inner diameter of the subterranean casing.
 2. The object of claim 1, wherein the object is sized to sealingly engage with a landing profile at a distal end of the subterranean casing.
 3. The object of claim 2, wherein the deformable layer comprises at least one of a foam, a gel, and a rubber.
 4. The object of claim 3, wherein the inner core comprises at least one of a composite material and a thermal plastic.
 5. The object of claim 3, wherein the inner core comprises a metal.
 6. The object of claim 2, wherein the landing profile comprises at least one other baffle within the subterranean casing.
 7. The object of claim 1, wherein the subterranean casing comprises a casing string, and wherein the at least one baffle is included in a production sleeve included within the casing string.
 8. The object of claim 1, wherein the object includes a spherical shape.
 9. A method for wiping a subterranean casing, comprising: introducing an object into a subterranean casing, wherein the object comprises as inner core and a deformable layer surrounding the inner core, and wherein the deformable layer contacts an inner surface of the subterranean casing; forcing the object through at least one baffle within the subterranean casing; and causing the object to sealingly engage with a landing profile at a distal end of the subterranean casing.
 10. The method of claim 9, wherein: the inner core has a first width, the first width is smaller than a diameter of the at least one baffle, the deformable layer has a second width, and the second width is larger than or equal to a diameter of the inner surface of the subterranean casing.
 11. The method of claim 10, wherein the deformable layer comprises at least one of a foam, a gel, and a rubber.
 12. The method of claim 11, wherein the inner core comprises at least one of a composite material and a thermal plastic.
 13. The method of claim 11, wherein the inner core comprises a metal.
 14. The method of claim 10, wherein the landing profile comprises at least one other baffle within the subterranean casing.
 15. The method of claim 9, wherein the subterranean casing comprises a casing string, wherein the at least one baffle is included in a production sleeve included within the casing string.
 16. The method of claim 9, wherein the object includes a spherical shape.
 17. A system for subterranean operations, comprising: a casing string, wherein the casing string includes a landing profile at a distal end; a plurality of sleeves disposed within the casing string, wherein each of the plurality of sleeves includes a baffle; and an object comprising an inner core and a deformable outer layer surrounding the inner core, wherein: the inner core has a first width, the first width is smaller than a diameter of at least one baffle included in the plurality of sleeves, the deformable layer has a second width, and the second width is larger than or equal to a largest inner diameter of the casing string.
 18. The system of claim 17, wherein the object is sized to sealingly engage with the landing profile.
 19. The system of claim 18, wherein the deformable layer comprises at least one of a foam, and gel, and a rubber.
 20. The system of claim 19, wherein the inner core comprises at least one of a spherical composite material and a spherical thermal plastic. 